Fix build with Linux 5.3

Use uint for module parameter type for setup_timeout, remove -ve check

In Linux 5.3 nf_ct_expect_related() gained a flags argument.
Calls to this function are sprinkled throughout a couple of
source files, so rather than adding a #if to each call site, add
a wrapper which will use the appropriate prototype.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>

The module parameter setup_timeout is an unsigned int, so use uint
for a module parameter type. Since it is never going to be negative
also remove the redundant less than zero sanity check too. Issue
found with static analysis.

Addresses-Coverity: ("Unsigned compared against 0")
Signed-off-by: Colin Ian King <colin.king@canonical.com>

linux 4.18 uses a new struct nf_nat_range2 for nf_nat_setup_info.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

rtcp port mapping and other fixes

also codestyle fixes, parser fixes,
teardown handling and etc.

also codestyle fixes, parser fixes,
teardown handling and etc.

Since the arrival of IPv6 NAT, the related code has become more generic.
The RTSP module must also follow these changes to compile and run:
 - new "protoff" argument on some functions,
 - new includes because nf_nat_rule.h doesn't exist anymore.

Thanks to Benoit Lorand who pointed me to this needed change for kernel
version 3.6.

Some #defines and a struct got renamed in 3.3 so change them
accordingly.

NIPQUAD no longer exists so replace it with the %pI4 format extension.

To install the modules you should of course call modules_install.

Used a proper textwdith for the document.

Instead of having a patch, this is no setup up as an external module via
the kbuild system.

 * Remove double pointer **pskb
 * Reploace DEBUGP with pr_debug